Evaluation of NO-suppressing activity of several Mediterranean culinary spices

Po Jung Tsai, Tzung Hsun Tsai, Chun Hsien Yu, Su Chen Ho*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

82 Citations (Scopus)


Excess nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is implicated in the development of a number of diseases. Due to the absence of any natural specific enzymatic defense system in vivo, the consumption of certain foods which exhibit selective suppressive ability as regards NO overproduction might boost the host's protective effects against NO-mediated toxicity. Spices, rich in phenolics, are speculated conceivably to act as potential NO-scavengers or iNOS suppressors. The relative NO-suppressing activity of methanol extracts deriving from nine Mediterranean culinary spices was determined by measuring their inhibitory effect upon NO production for lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. In addition, the specifics of the suppressing mechanism were further explored. All of the spices tested, with the exception of clove, displayed a rather linear dose-dependent NO-suppressing effect without there appearing to exist any effect upon cell viability. Furthermore, the NO-suppressing capacity of certain spices was able to be ranked based upon their IC50 (the concentration of spice extracts is required to cause 50% inhibition of NO production by LPS-activated RAW 264.7 cells), the ranking appearing as: rosemary (0.031%) > tarragon (0.052%) > cinnamon (0.059%) > oregano (0.106%) > basil (0.162%) > marjoram (0.236%) > allspice (0.269%) > and thyme (0.270%). Only cinnamon displayed excellent NO-scavenging ability, whereas all of the other spices demonstrated moderate to poor activities in this regard. Moreover, the inhibitory effect of tested spices upon the iNOS protein level was almost equivalent to their suppressive effect upon NO production. It would appear that inhibition of iNOS expression was the primary mechanism of action of spices as regards their exerting NO-suppressing activity.

Original languageEnglish
Pages (from-to)440-447
Number of pages8
JournalFood and Chemical Toxicology
Issue number3
Publication statusPublished - 2007 Mar
Externally publishedYes


  • Antioxidant
  • Nitric oxide
  • Phenolics
  • Reactive nitrogen species
  • Spices

ASJC Scopus subject areas

  • Food Science
  • Toxicology


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